also, check out the sticky in the colorized photographs area regarding how collodion reproduces colors. you must take into consideration that these photographs are not black and white in the way we understand it. modern black and white is panchromatic - sensitive to all colors. Collodion was only sensitive to a narrow range of colors, primarily in the blue color spectrum. Colors like yellow and red would appear black on a collodion print. If you look closely, you will see a border on the shoulder straps, only slightly different than the rest of the colors. Colors such as yellow would only show the smaller amount of light of other colors that it also reflected. for example, with the star most likely being polished, it would reflect some colors other that the yellow/brass color ( or it may have been silver) which would make it look different than a non-reflective finish such as a gold border.